I bought a 7870 myst a few weeks ago and I'm mostly happy with it. Except for the Physx performance - I tried playing borderlands 2 again last night with it and with the Physx stuff turned up it was really choppy and stuttering.

I remember reading a while back that you can plug in a dedicated NVidia card for Physx:

1st question: Anyone know how to do this and get it to work?

2nd question: What's the best card I can use for this. I'm running a MSI P67A-GD65/2500K with a HX620 PS. I'm not overclocking anything, so when everything is going at max I'm using ~300W. I have a Zotac 560 ti 448 but that will eat about 200W if I stick it in. So I'm looking to get a lower powered (6xx series) card to use for this. Any suggestions?